基于远场光分布测量微透镜面形误差峰谷值的方法

针对传统微透镜面形测试光路复杂和效率不高的问题,提出了一种基于微透镜远场光斑高效提取环带状面形误差峰谷（PV）值的方法。基于几何光学原理,计算了不同环带误差形成的光斑的分界线位置;建立了环带误差的三维模型,通过仿真不同误差模型下的远场光斑,获得了分界线内外光强比值和环带误差值的对应关系;最后利用微纳加工技术制备出不同环带误差的微透镜阵列,搭建测试光路,通过测试获得了不同环带误差下的光斑能量分布,通过模型计算获得的微透镜环带状面形误差PV值与干涉仪测试结果一致。     

GRIN透镜红外波段焦斑直径的测量

主要介绍ＧＲＩＮ透镜在红外波段聚焦光斑直径的测量方法及误差分析。     

锥形透镜光纤聚焦特性研究

锥形透镜光纤(TLF)是实现光纤与平面光波光路(PLC)芯片高效耦合的核心元件。了解和掌握其聚焦特性是指导平面光波光路尾纤封装技术的关键。给出了表征锥形透镜光纤聚焦特性的两个参量出射光斑直径和远场发散角的理论分析模型,其误差小于1.14%;采用光束传播法数值模拟了锥形透镜光纤中的光波传输和模斑的演化,确定了锥形透镜光纤端面出射光斑的大小;优化锥形透镜光纤结构参量为:拉锥长度300μm,锥角0.733°,透镜曲率半径13.485μm;建立了基于数字摄像机的锥形透镜光纤出射光场测试系统,提出了物理光学反向推演法,计算出锥形透镜光纤聚焦光斑尺寸和远场发散角。理论与实验结果有着良好的一致:对于相同结构参量的锥形透镜光纤,实验反推法得到的出射光斑尺寸与理论值相比误差为3.15%,远场发散角误差为3.67%。     

微透镜阵列误差对半导体激光匀化性能的影响

为了减小微透镜阵列误差对匀化光斑的影响,深入研究微透镜阵列光束匀化系统中微透镜阵列相对位置误差对光束匀化性能的影响,设计了一种微透镜阵列光束匀化系统。依据相对位置误差类型的不同,将双列微透镜阵列间六个自由度变化导致的误差分为距离误差、偏移误差以及转动误差进行分析,并对每种误差对光束匀化性能的影响进行了研究。采用6板条半导体激光器堆栈对上述匀化系统进行实验验证,实现了均匀性为90.75%的光斑,并对系统影响光斑性能的原因进行了分析。     

非球面液滴微透镜固化控制和焦斑测量研究

利用电场改变液滴透镜的面形得到非球面,并实时检测其面形和焦斑图像,在适当的时候用紫外光固化液滴制作具有良好光学性能的非球面微透镜.比较了非球面液滴微透镜在固化前后面形、焦斑的变化和对透镜性能的影响,讨论了液滴透镜在固化过程中变形的机理和相应的解决方法.用分辨率50 nm的光斑探针扫描仪精确测量了固化后的非球面微透镜的聚焦光斑,测得了光斑轴向分布曲线和均方根直径3.384μm的聚焦光斑,经图像处理计算了透镜的点扩散函数和光学传递函数,评价了所制作的非球面微透镜的聚光和成像能力,并给出了透镜的实际成像图像,对于完善高品质非球面微透镜及其阵列的制作工艺具有重要意义.     

光纤波束传输系统

光纤波束传输系统ＯＤＣ－１００系列光纤波束传输系统可传输精密加工和其它材料处理方面要求将激光功率耦合到１００～１０００μｍ光纤的激光功率。此系统装有透镜组件。光纤的尺寸由功率电平和聚焦光斑大小确定。聚焦透镜组件增大了纤芯（４：１），它一个可选择穿孔和...     

基于透镜畸变效应的仿人眼扫描系统设计

仿人眼扫描具有旋转与尺度不变性、背景信息压缩及变分辨率信息采集等优点,但传统的仿人眼扫描方法存在系统结构复杂、扫描速度慢等缺点,提出一种基于透镜畸变实现扫描环增长,采用阿贝棱镜旋转实现对目标视场扫描的仿人眼扫描方法。利用透镜畸变对不同视场下入射光斑进行放大,进而实现仿人眼光斑结构。通过物像关系求解透镜初始参数,将仿人眼扫描光斑的环间增长系数作为透镜畸变优化目标函数,对透镜参数进行非球面优化,获得透镜结构参数。设计的仿人眼扫描系统焦距为14.24 mm,工作距离为25 mm。仿真结果表明:入射高度为20 mm的1×16线阵激光能够对直径为27.66 mm的像面实现16环仿人眼扫描,扫描光斑的最大环增长系数为1.08。相比于传统仿人眼扫描方式,此文提出的方法具有成本低、结构简单、扫描速度快等优点。     

自聚焦透镜的光斑尺寸与像差特性分析

对自聚焦透镜的光斑尺寸和像差特性进行了理论分析.利用自聚焦透镜光斑测量系统对样品的出射光斑进行了扫描,测得了光斑的大小；用读数显微镜和正方形网格图分别测量了样品的球差和畸变,并对光斑的测量作了误差分析,讨论了球差与畸变、光斑和像差之间的关系.所得结果对光斑质量的改善、像差特性的研究和自聚焦透镜的评估有一定的参考价值.     

平行光管测量透镜分辨率中观察系统对结果的影响及其它有关问题分析

透镜分辨率是透镜的重要参数之一，对理想透镜，通常用瑞利判据给出最小分辨率弧度，式中λ为光波波长，D为透镜直径，付立叶光学从频谱的角度分析，对于相干光给出了对于强度而言的透镜空间截止频率以及对于非相干光的对于复振幅而言的截止频率不难得出，所确定的透镜分辨率对于相干光来说不小于瑞利判据所给出分辨效率的二分之一（），至于非理想透镜，因为存在像差和色差，分辨率小于同一孔径的理想透镜，除了通过比较复杂的光学传递函数测定从而确定透镜的分辨率之外，通常采用比较简便的用平行光管直接测定透镜的分辨率，这是普物光学…     

频谱编码内窥成像技术

频谱编码成像技术是一种利用光栅在横向位置编码的新型生物组织成像技术。该技术采用一个光栅和一个聚焦透镜在样品上产生光谱编码线,无需额外扫描便可得到一条线的图像,跟频域干涉技术相结合,再加上慢速的线扫描便可获得三维图像,在内窥成像上具有很大的实用价值。在分析频谱编码成像技术基本原理的基础上,推导了主要的性能参数。通过对分辨率测试靶进行成像,验证分析影响横向分辨率的因素。结果表明,编码线方向的分辨率与入射光斑直径成反比,与焦距成正比;垂直于编码线方向分辨率要弱于编码线方向的分辨率。最后对洋葱样品进行成像,验证了频谱编码成像技术的可行性。     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.     

A stereo matching algorithm using multi-peak candidate matches and geometric constraints

Gray cross correlation matching technique is adopted to extract candidate matches with gray cross correla- tion coefficients less than some certain range of maximal correlation coefficient called multi-peak candidate matches. Multi-peak candidates are extracted corresponding to three closest feature points at first. The corresponding multi-peak candidate matches are used to construct the model polygon. Correspondence is determined based on the local geometric relations between the three feature points and the multi-peak candidates. The disparity test and the global consistency checkout are applied to eliminate the remaining ambiguous matches that are not removed by the local geometric relational test. Experimental results show that the proposed algorithm is feasible and accurate.